Exactly my experience. Yet, I believe app will not only provide data but also some custom, short lived UI widgets in places where a more specific and consistent UX makes sense. But apps will definitively lose control over the navigation and even lose track of the user (they will identify and authorize only one : the harness; who sits behind will remain a mystery)

I've written about this "UI to AI" pivot for my own Saas (cloudywithachanceoflatency.net). I believe it's a big win/win for every party.